Gauge



June 5, 1945. a. R. ECKSTEIN 2,377,679

GAUGE Filed Sept. 14, 1943 2 Sheets-Sheet 1 N 26 Z 1 m 5 mvE TbR. GEORGE A. [cm-7'51 RNETS June 5, 1945.

R. ECKSTEIN GAUGE File'd Sept. 14, 1943 2 Sheets-Sheet 2 INVENTOR. 60R6 A? fcmrrr/m ATTORNEYS cause.) 1

Patented June 5, 1945 UNITED'STATE )QFFI CE b l Remington Arms Company, 'Inc;; Bridgeporh rill. l I

Conn., a corporation ofDelawaref Application September 14, J

2 Claims. ((133-118) 1 The present invention relates to a gauge and is particularly; adapted for the gaugingof' apertures or bores having allowable limits in dimensions such as, for example, a die for assembling and shaping bullets.

It frequently is necessary to gauge apertures to determineif the dimensions thereof tall within certain limits. When these apertures are extended in length, it is also desirable to be able to determine if there are any.undercut portions and to determine if the dimensions are within the tolerances throughout the length of the bore. It the walls are tapered it is also desirable to gauge the diameter for the full length; ofthe bore. l

The invention is described herein in conjunctionwith its use in determining the contour of "abulletassembly die such as used inthe manufacturef of small arms ammunition, but it isto be distinctly understood that it is not limited thereto. These and other objects of the invem tionfwill'appear from the following description. Fig. l is" a side view of one-form of i gauge Twhichmaybe used; y b Fig. zfshows the use ofjsuch a gaugefor deter-- mining the minimum bore as the gauge ap fproachjthe' b'asicbore.

Fig. 3 is similar to Fig. which is too large.

13718.14 show the ideal bore has the desiredcontouru C Fig. 5'shows the gauging of the bore near the opening thereof at which pointjthe bore is too large. l l l bore. f. Fig. ,7 shows graphically the geometrical derijvation used in determining the radius of the ellipsoidal portions of the button or knob of the Fig. B'shows graphically the geometrical deri- ,vation used to determine, the angle through which the gauge must swingat theheel position. 'Fig. 9 is a diagrammatic. view showing the path of gauging if the necessary inithei quantity production .of small armsammunitijonlf" .l I

The' present gauge will also indicate whether or not there are anyundercuts in the profile oi the die. If there are undercuts, it is obvious that it will be difi icult to withdraw the bullet fromthe 2 and-shows a bore Fig 6 showstheeiiect of an undercutin the directions in which the handle may be moved so as to check theroundnessoi the bore.

In thedesign andproductionof bullet dies, it is essential that the contour andsize thereof fall within certain. predetermined tolerances and these tolerances are extremely small. It is also desirable thatbullet assembly dies have a slight diel The' gauge comparatively simple, easy to m'ak'e,' and has a rather large wearing surface. The" gauge comprises an' ellipsoidal portion or button with a shank extending therefrom, the shank having a predetermined shape relativefto the buttonaiidthe =holetobe gauged. As employed herein, the-term ellipsoidal means a suriaceof revolutionwliich falls between a sphere having a. radius of the minimum diameter or the basic bore, and a cylinder having the minimum radius of the basic bore. The basic bore is considered the diameter at the innermost point of the hole which isto be gauged. The shank may be tapered,}such as isshown in Fig. 2 at ZKLand attached to the ellipsoidal portion 2|. Shank 20 may also have a handle 22. The method of use of the gauge willbe described and then the manner in which the dimensions thereof. can be calculated. A

In Fig. 2, 23 is a cross-sectional View of a con- .ventional bullet assembly die. The basic bore is at 24 t at some predetermined distance M from theend of the die. The exact location of the basic bore may or may not be critical. To the right of the basic bore, the bullet die can have a conventional ogive shape 25. The heel 26 of the bullet is located at a distance N from the end "Zlgof the die. The distance across the ellipsoidal buttonll' at right angles to the axis of the die is made the minimum diameter of the bore at this point. The ellipsoidal portion is designed in conjunction with thetapered shank so that if the bore at 24 is the maximum or more, the shank 20 will touch the side of the die at 28 as shown in Fig. 3. If the shank does not touch and enters to the. desired depth, the bore is within the tolerances for which the gauge is designed. The taper of the shank is selected and related to the ellipsoidal button so that when the: bore at the heel is to be gauged the shank will not touch the side of the die if the bore at the heel is Within the selected tolerances.

Referring to Fig. 5, the shank is shown touching the side of the die atZQindicating that the .-bore at the heel is too large. The idea1 path of gauging is shownilnFig l whereinthe side'of the equation undercut in the bore at any point, the gauge will strike the side of the die near the mouth as shown in Fig. 6 or the handle will change from a smooth line of travel as it is pulled out of the bore. The gauge might even jam at the undercut. Any of these will give notice to the gauge operator that there is an undercut. I

The roundness of; the bore can be determined by moving the handle back and forth in two directions or as many directions as desired, a shown by the arrows in Fig. 9.

The gauge may be designed as described here-Q after but it is to be understood that the gauge is not limited to such a shape. Referring to Fig.

1, A is the minimum allowable basic bore, Bis the .depth of the bore, is the mouth radius. of

the die, D is an arbitrary diameter which may be selected. As an example thereof; D can be made .125 inch for caliber .30 bullet assembly dies and" .321 inch for caliber .50 bullet assembly dies.

than a minimum, therewill. bee slight change in I the gauging point... which is, immaterial. .The radius G of, the. ellipsoidal button can be deter mined. Reierencebeing made toFig. 7, G is the quantity to, be solved for andthe .sideUOP. isthe common side of triangles ORP. and OQP. OR.

being the quantity G. The side 0Q is composed of M and half the tolerance. The side PQ is the cosine '0 of the angle of swing times the hypotenuse,

Then G may be solved for as follows: i

g 2 2, 3 2.2. t t .31

I ewes) GA-4f-2G cos angle 2 "\Acos angle t Then let F be the distance from the mouth of the die to the bullet heel and S the tolerance of the die bore at the heel. Referring to Fig. 8, the angle of swing of the gauge at the bore can be determined by solving the two triangles having a common side WT as follows:

[cos angle cane-( a) 4 cos ang1e= The tangent of the angle of; swing atthe can be determined from trigonometric tables-and from this-the diameter E may be calculated ln accordance with the formula E:=A- (tanof an;- gle) 2F. The distanceI-l depends on the being gauged and can be arbitrarily selecte as $17 for caliber .30 dies and?? for 'c'aliber'fif) The shape of the sham; maybe made'jother than a straight taperii it; is desiredgto gauie a hole not having a straight taper. Itisals'o "an;- parent that the handle need not take the'shape illustrated. A mark or se'riesl of marks Yca'nibe placed on the shank whichmaybe aligne'd'with the end of the die to indicate th d th e'ij'the gauge. The gauge of the present invention is simpllef'to Construct, to use, arid'lsfadaptedliof 281.1 8 6161. .9. number of dimensions or characteristics; i Whatis claimed is: I Y '1. A tolerance gauge for elongated 'circ ar apertures comprising an ellipsoidal button oin ne end and a shank extending therefrom, said'shank having a predetermined profile relative to said-ellip'soidal button, the joinder 'of saidsfianlgffwith said button being of a reduceddimensioh and spaced from the point of minimum diameterbi said button a distance such that the shank said reduced point will not touch the walls of; an aperture of less than maximum size when the button is gauging a portion adjacent the aperture mouth, and the transverseidimension of the extended portion of theshank being uchthat'it will not touch the walls of said 'aperture when the deepest part of the aperture is less than ina gspaced from the point of minimum diameter of said button a distance such that the shank at said reduced point will not touch the walls of an aperture of less than maximum size when the button is gauging a portion adjacent the aperture mouth, and the transverse dimension of the extended portion of the hank being such that it will not touch the walls of said aperture when the deepest part of the aperture is less than maximum size, said shank being shaped so as not to touch the walls of said aperture when intermediate points are being gauged which are less than the maximum size.

GEORGE R.'ECKSTEIN. 

